thanks rstofer, in the meantime I analyze d / dt (as soon as I archive this I read well your intervention 674 for the integrated)
I'm starting to understand something, and I also learned what slew rate is in op.amp datasheets
If I look at your test with the Rigol, I see that if you enable the diff function, the display shows you the value that is 1MV / s, and everything makes sense.
Now look at my attached image: usual compensation signal, as you can see the square wave values are 3.12v and a rise time of 984ns.
As you taught me, the d / dt should be: 3.12v / 0.000000984s = 3170731V / s
As you can see, the only data he shows me related to d / dt are the vertical divs (100kv / s) and the position on the display.
What good can this view be for me, if it doesn't even tell me the d / dt value? or maybe I'm missing something?
In your Rigol it makes sense, you enable the diff and it indicates the V / s relative to the ramp rise time of the signal ... but in my Siglent what do I do with this d / dt graph?
http://chalkdustmagazine.com/features/analogue-computing-fun-differential-equations/
It scared me when my grandson had to take Differential Equations last semester. I struggled with it back in college because, among other things, we didn't have much beyond a slide rule to work with them. Today it's all done in MATLAB using the ODE45 solver or even programming up a version of Euler's solution. Its almost trivial. When I took the course, I did have access to a computer and plotter. What I didn't have, and what wasn't presented, was a computer method for solving.
Yes, that's the rise time as typically defined. The thing is, the derivative function starts a 0V and you can see where the upper 10% is quite rounded. As far as the derivative is concerned, things start changing earlier and end much later and dt is therefore a longer period and the MV/dt is less
When it comes to differential equations, things start to get pretty complicated—or at least that’s what it looks like. When I studied mathematics, lectures on differential equations were considered to be amongst the hardest and most abstract of all and, to be honest, I feared them because they really were incredibly formalistic and dry. This is a pity as differential equations make nature tick and there are few things more fascinating than them.
it is no coincidence that I have been stopped for 10 days between FFT, diff etc ...
When it comes to differential equations, things start to get pretty complicated—or at least that’s what it looks like. When I studied mathematics, lectures on differential equations were considered to be amongst the hardest and most abstract of all and, to be honest, I feared them because they really were incredibly formalistic and dry. This is a pity as differential equations make nature tick and there are few things more fascinating than them.
it is no coincidence that I have been stopped for 10 days between FFT, diff etc ...Differential calculus is much easier to understand if you approach it from Physics. While it won't be so rigurous, it will become much more intuitive. That's why explaining the meaning of the Fourier transform using sound makes it much easier to understand.
I downloaded the pdf of this review (siglent 1104, but the diff function seems the same to me)
https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/
3° post /1* pdf
where for the differential it states:
This is a particularly cumbersome math function that just cannot work well on an 8 bit system. It has a
parameter dx, which determines the interval used for the difference computation. For an accurate and
detailed result, we would want dx to be as small as possible and the lowest value that can be set is 0.02
div. With this setting, we can get totally useless results, as we will see later.
Differential calculus is much easier to understand if you approach it from Physics. While it won't be so rigurous, it will become much more intuitive. That's why explaining the meaning of the Fourier transform using sound makes it much easier to understand.
Nice find! It may turn out that some of the functions just work for very specific examples and are not generally useful. Mostly I just use the scope for looking at squiggly lines - waveforms. Maybe someday I'll have an application for the more exotic math functions but I'm not counting on it.
I'm sure there is a lot to learn from that review. It is the longest running review I have ever seen.
At my age (74) mid afternoon naps are becoming more common. Mid morning naps are popular as well. Plus another nap while watching TV before bed time.dont you regularly go to Wallmart/McDonalds anymore?
If it fits in between my naps...
I have been retired, and comfortably, for 17 years. I get to play, and nap, as much as I want and never have to commute.
Social distancing hasn't been a problem, I've been doing it since I retired.
At my age (74) mid afternoon naps are becoming more common. Mid morning naps are popular as well. Plus another nap while watching TV before bed time.dont you regularly go to Wallmart/McDonalds anymore?
If it fits in between my naps...
I have been retired, and comfortably, for 17 years. I get to play, and nap, as much as I want and never have to commute.
Social distancing hasn't been a problem, I've been doing it since I retired.so you've been scamming us all these years? how dissapointing i've been saving money to buy plane's ticket to your place in hope i can get some good and joyful lesson, cheap wallet an all... now what i'm gonna do? anyway i hope you are doing well..
Skipping ahead to the integral, the scope does the obvious calculus things.
The first image shows the integral of a constant and then what happens when the constant changes - a square wave. The integral (c dt) is c*t where t is the time over which the integration occurs. As time goes by, the product c*t increases linearly - this results in a ramp. In the product, the only thing that is changing is linear time, the constant is, well, constant. When the constant changes, the ramp heads in the other direction. This is integration at its easiest and is the basis for analog computing.
Pour a constant 5 gallons per minute into a 50 gallon barrel and plot the height of the water over time up to 10 minutes when it overflows.
The second image shows the integral of the sin(x) function (waveform) and the integral(sin(x)) is -cos(x) plus a constant which I will ignore. Note the middle of the screen where the yellow sin(x) crosses 0V going positive and the blue is at its minimum value (not 0 but some negative value). In a perfect world where the sin(x) varied from 0 to +1 to 0 to -1 and back to 0, the cos(x) would vary from +1 to 0 to -1 to 0 and back to +1 and -cos(x) would vary from -1 to 0 to +1 to 0 and back to -1. I don't know why my Rigol isn't displaying the magnitude of -cos(x) properly but the idea is right. It shows a cosine but the upper and lower values are wrong. I'll probably have to read the manual.
See the screen image from Desmos.com The red trace is sin(x) and the green trace is -cos(x).
Here is a table of simple integrals from Calculus II:
https://www.mathsisfun.com/calculus/integration-rules.html
In any event, integration may be important. The voltage on a capacitor is 1/C * integral(i dt). This makes sense because a larger capacitor takes more current (or more time) to charge to the applied voltage. Double the size of the capacitor and it takes twice as long to charge to some voltage given an identical current. Again, this makes sense.
You can think of an integrator (or capacitor) as a bucket that accumulates something - perhaps charge. Or the pressure in an air compressor tank. When empty it starts at 0 psi and as the pump runs, more air is accumulated in a fixed volume so the pressure increases. Or the barrel of water described above.
The second image shows the integral of the sin(x) function (waveform) and the integral(sin(x)) is -cos(x) plus a constant which I will ignore. Note the middle of the screen where the yellow sin(x) crosses 0V going positive and the blue is at its minimum value (not 0 but some negative value). In a perfect world where the sin(x) varied from 0 to +1 to 0 to -1 and back to 0, the cos(x) would vary from +1 to 0 to -1 to 0 and back to +1 and -cos(x) would vary from -1 to 0 to +1 to 0 and back to -1. I don't know why my Rigol isn't displaying the magnitude of -cos(x) properly but the idea is right. It shows a cosine but the upper and lower values are wrong. I'll probably have to read the manual.
See the screen image from Desmos.com The red trace is sin(x) and the green trace is -cos(x).
The question that comes to me would be: but in reality what does zero time represent in a circuit where a signal like these flows? Or when can I say, looking at a sine wave with the oscilloscope, if this is sin, cos or -cos?
You can shift any one of those function graphs to the left or to the right to basically fully overlap with another (their pattern is the same, just their starts are different). Unless you have a reference point that serves as "time 0", there is no way to distinguish these three from one another, so you could pick any one of them and be right.
ACpowervoltage that you could theoretically measure from your power outlets (disclaimer: please don't, if you do not know exactly what you're doing) closely follows a sine wave (or cosine wave, they're basically identical). "closely" because even though in theory the generation at the very start of the power line would be a true sine wave, much happens in between (until your outlet is reached): inductance and capacitance from all kinds of components and whatnot is super-imposed onto that 50 Hz base frequency. If you looked at it with a 'scope, I suspect you'd see some "wiggling" and high-frequency content.
You are right!